It has been found impractical to utilize free-standing thermoplastic containers having conventionally designed, push-up bottoms for packaging products which will be frozen in the container. The conventional push-up bottom has a circular center portion which is connected to the bottom of the container body by a circular connecting wall. The angle of intersection between the circular portion and the circular connecting wall is constant throughout the circumference of the intersection. When this conventional design is utilized, the expansion of the product, when it freezes, pushes the bottom wall out thereby deforming the container so that it cannot be stood on its bottom. To overcome this difficulty it has been suggested that the bottom of the container be made with a greater wall thickness or that the container be provided with additional structure to reinforce the bottom wall. These solutions are not desirable as they require special programming of the parison or require intricate mold designs.
Therefore it is an object of this invention to provide a container having a bottom wall configuration which is capable of withstanding freezing expansion of the container product without deformation. It is a further object of this invention to provide such a container without requiring added thicknesses in the bottom wall or requiring additional complex wall structure.